ABSTRACT
Environmental threats often trigger innate defensive responses in mammals. However, the gradual development of functional properties of these responses during the postnatal development stage remains unclear. Here, we report that looming stimulation in mice evoked flight behavior commencing at P14-16 and had fully developed by P20-24. The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage. Furthermore, the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24. Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and provide important insight into the underlying mechanism.
Subject(s)
Animals , Mice , Evoked Potentials, Visual , Fear/physiology , Mammals , Mice, Inbred C57BL , Neurons/physiology , Superior Colliculi/physiologyABSTRACT
To investigate the tissue-specific and stage-specific expressions of porteins relatedto cell death or survival in development of rat eye, Bcl-2, Bax and p53 as well as PCNA were studied from 14th day of embryonic stage(E14) to 22th day of opstnatal stage(P22) every other day in Spragur-Dawley(SD) rats. Expression of these gene proteins was studied by immunohistochemistry. At E14, Bcl-2, Bax and PCNA were expressed on the surface ectoderm and anterior lens epithelium. p53 was highly expressed in theposterior lens epithelium and in the inner layer of retina. PCNA was highly expressed in the middle layer of retina. In postnatal stage, In the retina, Bax and PCNA were expressed throughout whole layers and p53 was stained in the middle layer, However, Bax, p53 and PCNA disappeared after P14, wherase Bcl-2 still remained by P22. In the lens, p53 expression was detected by P14 and then disappeared. In the iris. Bax and PCNA were highly expressed between P0 and P22. These results indicate that Bcl-2, Bax and p53 may contribute to the development of rat eye. The expressions of Bcl-2, and Bax, p53 are not conducted step by step but overlapped and expressed in different stages depending on ocular tissue.